A British Muslim activist was arrested after he refused to handover the password to his laptop and mobile phone when he was stopped by police at London’s Heathrow airport in November.

Muhammad Rabbani, the international director of the campaign group Cage, was released on bail after the incident and could be charged under terrorism laws when he reports to the authorities on Wednesday.

The 35-year-old was held under Schedule 7 of the Terrorism Act, which gives police a broad range of powers to search individuals at ports of entry without grounds for suspicion.

Cage, which provides legal advocacy for those affected by British terrorism legislation, said Rabbani’s devices contained details about an "investigation into torture complicity by a UK ally."

According to the organisation, Rabbani agreed to share details on the devices relating to himself, but not information about Cage’s clients, which he said would constitute a breach of confidentiality.

It said after his refusal to handover the credentials, the devices were seized by the police and have not been returned to Rabbani since.

"I’m facing prison due to the existence of a power that has been operating at the UK borders for 17 years now," Rabbani said in a statement.

"Using this power, officers can compel a person to surrender their passwords without cause and there’s also no right to remain silent."

No suggestion of offence

Cage said police officers had assured Rabbani that he was not being accused of any crime, and it questioned why such powers were being used when there was no suggestion of an offence being committed.

Ibrahim Mohamoud, Cage spokesperson, said "governments should not interfere in the work of human rights defenders, especially those investigating international law violations such as torture".

He said the incident had disrupted an ongoing investigation Cage was carrying out, without specifying details about the case.

The Metropolitan Police, which is responsible for the Greater London area, does not name individuals who are the subject of investigations, in accordance with its policies.

In a statement sent to Al Jazeera, it said: "On Sunday, 20 November 2016, a 35-year-old man was stopped under schedule 7 of the Terrorism Act 2000 at Heathrow Airport."

"He was subsequently arrested under paragraph 18 of schedule 7 of the Terrorism Act 2000."

Schedule 7 powers

The legislation under which Rabbani was held has been frequently criticised by human rights groups for its allegedly discriminatory implementation and impact on civil liberties.

Under the powers police have, anything a person has on them can be confiscated, including communications and data storage devices.

The British civil liberties group Liberty described the law as "breathtakingly broad and intrusive" and said ethnic minorities were disproportionately targeted with Asians 42 times more likely to be stopped than white people.

The symbolical power of compelling one to hand over of passwords, the figurative boundary between the personal and the private sphere, is also a nascent frontier in the government’s ill-informed counter-terrorism strategy.

Tanzil Chowdhury, University of Manchester

"We’ve long argued that schedule 7 is ripe for misuse and discrimination," Liberty said on its website.

"We believe it contravenes the basic rights to liberty and respect for private life, as protected by the European Convention on Human Rights, and is therefore unlawful."

Tanzil Chowdhury of the University of Manchester's School of Law told Al Jazeera, the legislation was being used to "villify" communities.

"Schedule 7 ... has been used disproportionately against Muslim, Asian and Black communities," he said.

"In recent Home Office statistics, drops in the use of Schedule 7 power were noted among all ethnic groups except for Asians which saw a 2 percent increase in the year ending September 2015.

"This has the effect of vilifying an entire community who have to continually answer the charge of its imagined criminality."

Chowdhury also warned of of the negative message the police's handling of Rabbani's case sent to Muslims, and condemned the core infringement of a person's privacy.

"The symbolical power of compelling one to hand over of passwords, the figurative boundary between the personal and the private sphere, is also a nascent frontier in the government’s ill-informed counter-terrorism strategy."

Alleged abuse of the power came to international attention in 2013, when David Miranda, the partner of journalist Glenn Greenwald, was detained under schedule 7, also at Heathrow.

Miranda was held because authorities believed he was carrying filed relating to NSA whistleblower, Edward Snowden.